To deliver a medication in the mouth over time for treatment of health problems in the mouth or throat, oral patches have been developed. An oral patch typically includes one or more flexible layers that do not dissolve entirely such as invented by Anthony et al. and disclosed in U.S. Pat. No. 5,713,852. Another example of an oral patch is the DentiPatch which has one or more non-soluble thermo-plastic layers and lidocaine, offered for sale by Noven Pharmaceuticals, Inc.
As used herein, the word “patch” does not include preparations that move about the mouth rather than adhering in one place, such as cough drops or throat lozenges, and therefore do not maintain a high concentration of released medication in the desired spot. Nor does it include preparations that do not hold together as a single item when held in the mouth such as preparations of powder, liquid, paste, viscous liquid gel, or a tablet or troche that crumbles into a powder or paste when chewed or placed in saliva. Conversely, it does include an adherent preparation formed of a gelled hydrocolloid that holds together as a single item when held in the mouth, such as the adherent, soluble oral patch disclosed by the same inventor in U.S. patent application Ser. No. 10/287,843 filed Nov. 5, 2002, which is incorporated herein by this reference.
The most significant differences between an oral patch as used herein and other forms of medicinal preparations is that an oral patch is designed to release medication into the mouth over a relatively long period of time, such as 30 minutes of more, and be adherent to stay in one place so that the medication can reach high concentrations along side the patch, and remain in the mouth as a single item that will not spread to be in a plurality of location in the mouth at one time.
It has been known for many decades that licorice root (Glycyrrhiza) includes an ingredient that speeds the healing of ulcers in the stomach. It is not yet known which ingredient in licorice root is responsible. More recently it has been discovered that a majority of stomach ulcers are caused by bacteria called Helicobacter pylori and that most stomach ulcers are therefore treatable with pharmaceutical antibiotics. This suggests that the active ingredient in licorice root is an antimicrobial that interferes with the Helicobacter pylori bacteria or with a reaction of stomach tissues to the bacteria.
For treatment of ulcers in the stomach, powdered licorice root extract is sometimes swallowed in gelatin capsules. However, it is believed that the extract is more effective if it is mixed with saliva before being swallowed. Therefore, chewable licorice extract tablets and lozenges have been developed. The extract powder is compressed into a tablet or lozenge form that quickly crushes into a mass of powder or paste when chewed. Even if it is not chewed, when exposed to saliva, it quickly dissolves into a mass of past and mixes with saliva. All of these licorice extract tablets and lozenges are designed to be chewed and the resulting paste swallowed. It is not known to put licorice extract in an oral adhesive patch.
Physicians in India have determined with clinical trials that licorice extract is also effective for speeding the healing of ordinary mouth ulcers, commonly called canker sores, technically called aphthous ulcers, when the extract mixed with water is swished in the mouth several times per day. Das S K, Gulati A K, Singh V P; De-glycyrrhizinated Licorice in Aphthous Ulcers; J Assoc Physicians India, 1989, 37:647. It also quickly relieves pain from canker sores without numbing surrounding tissues.
Other physicians (Andrew Weil) have reported success in speeding the healing of canker sores using propolis, made by bees, which is believed to have antimicrobial effects.
As reported in standard medical references, topical application of pharmaceutical antibiotics such as tetracycline or penicillin have been shown to speed healing of canker sores (aphthous ulcers) when swished as a liquid in the mouth several times per day. Alternatively, antibiotics may be applied to the canker sore several times per day as a powder, paste, or viscous liquid gel or they may be placed into the mouth as a tablt or troche which quickly dissolves into a liquid or paste, as disclosed by Hau in U.S. Pat. No. 6,248,718, the contents of which are incorporated herein by this reference. In addition to tetracycline and penicillin, other antibiotics such as amoxicillin have been shown effective when applied topically in a similar manner. Other products that have been reported to speed healing of canker sores when applied topically include anti-bacterials such as hydrogen peroxide, carbamide peroxide, chlorhexidine gluconate and, in at least one study, the antihistamine diphenhydramine.
Anti-inflammatory drugs, such as corticosteroids, reduce severity of canker sores but do not speed healing.